| > there's not much of a difference in cost between steel+gravel and concrete is there? There is a difference, because a pure asphalt track is easy to lay, and especially easy to rework. Train tracks, especially those running in asphalt (shared road between cars and trams), have a host of problems: 1) It's really expensive to build them - trains weigh a LOT and the rails need adequate foundations 2) It's really expensive to maintain them - you can't just go with a miller over the asphalt, because there are, obviously, the rails themselves but also delicate wiring for positioning/switch controls, signalling etc.; also, in most cases there are no alternate routes, which means you have two weeks of no service at all where a bus might just be re-routed one parallel street away. 3) It's really expensive to keep them operational: unlike with rised rails, street-level sunk rails act as sinks for everything from ordinary dirt from leaves to stones idiots place in the rail or stuff that falls into the rail from improperly secured vehicles. 4) They're friggin' dangerous hazards for bicyclists! I can't count the number of falls and crashes I had due to being forced to escape into a sunken rail. 5) Idiots with huge trucks or who are not careful when operating stuff like lifters or excavators near the overhead wiring. Happens surprisingly often that someone accidentally damages or destroys overhead wiring. |